Documents and other data are often stored in electronic form. When files are stored on a network, it is often more convenient for a user to store that document locally for quicker access. However, where documents are subject to modification or revision by other users or by a central authority, the version stored locally may become obsolete.
In order to ensure that a user has the most up-to-date version of a file, systems that provide a notification when the document has been updated or has otherwise become obsolete have been developed. For example, document control systems may provide an email message providing such notification. However, such systems do not directly associate such notification with a locally stored file. Accordingly, a user that did not see the notification can open and use an obsolete file without being informed that the file is obsolete. In addition, a user must manually compare the document stored locally against the latest version, if verification that the file stored locally is actually obsolete is to be obtained.
Alternatively, a user may choose to always retrieve a document from a central repository at which the most current version is stored. However, this can result in greater access times. In particular, the user must download the entire document each time the user opens the file.